/**
 * Natural England ArcGIS REST API client for querying GB protected area layers.
 *
 * Queries the Natural England Open Data Geoportal (ArcGIS Online hosted feature services)
 * for environmental designations: SSSIs, SACs, SPAs, Ramsar sites, National Parks, and AONBs.
 *
 * All endpoints are free, require no API key, and are published under OGL v3.
 * Attribution: © Natural England copyright. Contains Ordnance Survey data © Crown copyright.
 */
export interface ConstraintLayerConfig {
    readonly slug: string;
    readonly constraintType: string;
    readonly nameField: string;
    readonly areaField: string | null;
}
export declare const GB_PROTECTED_AREA_LAYERS: readonly ConstraintLayerConfig[];
export interface ConstraintFeature {
    name: string;
    type: string;
    area_ha: number | null;
    source: string;
}
/**
 * Query a single Natural England ArcGIS feature layer for protected areas
 * intersecting a bounding box around the given point.
 */
export declare function queryLayer(layer: ConstraintLayerConfig, lat: number, lon: number, radiusKm: number): Promise<ConstraintFeature[]>;